Expansible drawer supports



June 4, 1957 E. c. BULLOCK EXPANSIBLE DRAWER SUPPORTS 2 Sheets-Sheet 1 K2 mm n 2 mu m 3 WWW r 1 0 c T mo A ,E A m 00 i O. A m w EY m B FiledOct. 1, 1952 June 4, 1957 E. c. BULLOCK EXFANSIBLE DRAWER SUPPORTS 2Sheets-Sheet Filed Oct. 1. 1952 FIG. 3

FIG. 4

FIG.

A 40 4| 42 L I INVENTOR. EARLE C. BULLOCK ATTORNEY FIG.

ait-ed htates Patent EXPANSHBLE DRAWER SUPPORTS Earle C. Bullock, GrandRapids, Mich, assignor to Steelcase Inc., Grand Rapids, Mich, acorporation of Michigan Application October 1, 1952, Serial No. 312,531

3 Claims. (Cl. 308-33) This invention relates to improvements inprogressive suspension or slides for slidably supporting file drawersand similar slidable elements, and more particularly to a constructioncomprised of a stationary or case rail, a rail attached to andtravelling with the drawer, and an intermediate extension rail which,when the drawer is moved in or out, automatically travels in the samedirection but at half the speed while maintaining the drawer in ahorizontal position. My invention relates to such a suspension in whichthe sliding members are mounted on ball bearings.

One of the objects of the invention is to provide a rigid and strongconstruction that will adequately support a loaded drawer when extendedfrom the cabinet, and which will operate easily and quietly duringdrawer movement.

A further object of the invention is to provide a practical, more freelyoperating and more economical method of preventing horizontal frictionalcontact between the case rail and intermediate rail, and theintermediate rail and the drawer rail. in my invention all side thrust,as well as vertical load, is transmitted by ball bearings or rollersinterposed between the sliding members, thereby eliminating directfrictional sliding contact between the fiat metal surfaces, usuallypresent in this type of suspension. In this manner, the drawer is causedto operate more accurately, easily and quietly, with less wear andwithout excessive side play.

These and other objects and purpose of my invention will be seen bythose acquainted with the design and construction of drawer suspensionsupon reading the following specification and the accompanying drawings.

In the drawings:

Figure l is a side elevation view of my drawer suspension in extendedposition.

Figure 2 is a side elevation view of my drawer suspension in closedposition.

Figure 3 is a side elevation view of the drawer rail for my drawersuspension.

Figure 4 is a side elevation view of the suspension rail for my drawersuspension.

Figure 5 is a side elevation view of the case rail for my drawersuspension.

Figure 6 is a sectional view VI-VI of Figure 2.

Figure 7 is a sectional view Vll-Vll of Figure 2.

Figure 8 is a sectional view VIII-VIII of Figure 2.

Figure 9 is a sectional view lX- iX of Figure 2.

Figure 10 is a sectional view taken along the plane XX of Figure 2.

Figure 11 is a fragmentary sectional view taken along the plane Xl-JG ofFigure 8. V

Figure 12 is an enlarged view of the bumpers used on certain of theballs in my drawer suspension.

taken along the plane taken along the plane taken along the plane takenalong the plane Figure 13 is a fragmentary sectional view taken along.

the plane Kill-XIII of Figure 11.

In executing the objects and purposes of my invention, I have provided adrawer suspension having a case rail, 3. suspension rail and a drawerrail, each telescopically related to the other. The loads imposed by thedrawer upon the drawer rail are transmitted to the case rail andsuspension rail by means of balls. These same balls are so arranged thatthey prevent side play between the drawer rail and the suspension memberand the suspension member and the case rail. Thus any side thrustimposed upon the drawer is transmitted through the balls and roller 40to the case rail, preventing any flat surface metal to metal contactbetween the telescoping members of the suspension.

In the following description the terms inwardly and outwardly arefrequently used and are to be taken to mean inwardly toward thegeometric center of the cabinet and outwardly away therefrom. The termsforwardly and rearwardly are also frequently used and are to be taken tomean forwardly in the direction of movement of the drawer as it isopened and rearwardly away therefrom.

The drawer suspension consists of three telescoping parts, the case rail1, the suspension rail 2 and the drawer rail 3. The case rail 1 consistsof a generally J-shaped member 4 having attached to its long leg anupwardly directed flange 5 (Figs. 1 and 7). The attachment of the flange5 to the J-shaped member 4 is preferably made by welding. The case rail.1 is provided with a large horizontally directed tab 6 (Figs. 1, 5 and6) on its rearward end and a pair of smaller vertical tabs 7 on itsforward end (Fig. 5). The tabs 6 and 7 secure the case rail 1 to theframe of the cabinet. Adjacent its upper end, the flange 5 is offsetinwardly to form a shoulder 8. The bottom of the J-shaped member iformed with a shallow, V shape groove to provide a track 12 for thehereinafter described main ball 20.

The suspension member 2 is nested within the case rail 1, its lowerportion being generally J-shaped and seating down within the lowerportion of the case rail 1. At a point substantially midway between itsupper and lower extremities the suspension member 2 is offset inwardlyto form a shoulder 9 below the shoulder 8 on the frame member 5. Theupper end 10 of the suspension member 2 is bent over upon itself in anoutwardly direction and hooks over the upper end of the flange 5.

Nested within the lower portion of both the case rail 1 and thesuspension member 2 is the lower portion of the drawer rail 3. Thedrawer rail 3 adjacent its lower end is offset outwardly to form ashoulder 11 above the track portion 12 of the case rail 1. At a pointslightly above the shoulder 11 the drawer rail is offset inwardly toprovide a shoulder 13 facing the shoulder 9 on the suspension member.The upper end 14 of the drawer rail is hooked outwardly and seats overthe hooked upper end 10 of the suspension member 2.

In the following description of the location of the ball bearingstransmitting the loads between each of the three members of the drawersuspension, it will be assumed that the drawer suspension is in closedposition and the balls are located as they are indicated in Fig. 2 andas they appear in Figs. 6 through 10.

Primary support for the suspension member 2 and drawer rail 3 isprovided by means of the main ball 25 (Figs. 2, 8 and ll). 'The mainball 29 is located substantially midway between the forward and rearwardends of the suspension. The main ball is nested within an opening '21formed in the lower portion of the suspension member 2 and is guided inits fore .and aft motion by. the upturned lips 22. The ball 20 is ofsuch diameter that its lower portion rests upon the track portion 12 ofthe case -rail 1 and its .upper surface supports the drawer rail 3 bybearing 'against'the lower face of the shoulder I 3 11. Thus, theprimary weight "of the drawer is transmitted directly from the drawerrail to the case channel, bypassing the suspension member. The main ball20 is of such diameter that, it-may contact the vertical; wall of thesuspension member 2 but does not touch the lower vertical leg 23 of thedrawer rail (Fig. 13). Thus the main ball is designed to transmitvertical loads only The remaining balls used in thesuspension structure,although at times transmitting a substantial portion of the weight ofthe drawer to the case channel, are also utilized to maintain properhorizontal alignment between the three members of the drawer suspensionas the drawer is opened and closed, as described hereinafter.

Rearwardly of the main ball 20 is an auxiliary ball 25 (Fig. 7), andforwardly from' the main ball 20 is an auxiliary ball 34 (Fig. 9). Bothof these balls are mounted in the raceway or track formed between theshoulder 9 on the suspension member and the shoulder 13 on the drawerrail. Inasmuch as ball 20 passes through the opening 21 of suspensionmember 2, it is apparent that ball 2!) supports drawer rail 3 by hearingagainst the lower face of shoulder 11, and drawer rail 3 in turnsupports the suspension member 2 by the balls 20 and 25 bearing againstthe upper face of shoulder 13 of the drawer rail and the lower face ofshoulder 9 of the suspension member.

Rearwardly of the main ball 20 is auxiliary ball 24 (Fig. 7), andforwardly from the main ball 26 is auxiliary ball 30 (Fig. 9). Both ofthese balls are mounted in the raceway or track formed between theshoulder 9 of the suspension member 2 and the shoulder 8 of the caserail 1. Inasmuch as the drawer rail 3 is pivotally supported by mainball 29, and suspension member 2 is supported on drawer rail 3 by balls25 and 20, suspension member 3 is also pivotally supported by main ball20. Therefore, when the drawer is heavily loaded in the rear, throwingthe balance of weight to the rear of ball 20, ball 30 will take thethrust and prevent the suspension and drawer rail from tipping up at thefront and down at the rear; conversely, when the drawer is heavilyloaded at the front, or the drawer is extended, throwing the balance ofthe Weight forwardly from the ball 20, ball 24 will take the thrust andprevent the suspension and drawer from tipping down at the front and upat the rear.

In addition to the vertical thrust carried by balls 25 and 34, theseballs are of such diameter that each contacts the vertical walls of boththe drawer rail 3 and the suspension member 2, transmitting side thrustfrom the drawer rail to the suspension member. Also, in addition to thevertical thrust carried by balls 24 and 30, these balls are of suchdiameter that they both contact the vertical walls of suspension member2 and case rail 1, transmitting .sidc thrust from the suspension memberto the case rail. These four balls take all sidewise or hori zontalthrust of the upper part of the suspension, preventing frictionalcontact of the vertical fiat surfaces.

Forwardly from the main ball 26 is also auxiliary ball 31 (Fig. 9),which is located between the lower track portion 32 of the suspensionmember 2 and the lower shoulder 11 of the drawer rail 3. Ball 31 isretained in position by a nesting wall 33. The nesting wall 33constitutes an angle welded to the top surface of the lower trackportion 32 of the suspension member 2 adjacent to and just forward ofthe main ball 20. The roller 40 extends thru a clearance opening 42(Fig. 11) in the vertical wall of the suspension member. The roller 40is of such diameter that it projects beyond the main ball 20 to contactthe vertical flange 23 of the drawer rail 3. The roller 4) projectsthrough the opening 42 to contact the vertical wall of the case rail 1and assure a minimum clearance A (Fig. 13) between the case rail 1 andthe suspension member 2. The roller 40 also assures a minimum clearanceB between the main ball 20 and the vertical flange 23. V The roller 40provides the only means in the lower portion of the suspension assemblyfor transmittinghorizontal side thrust from drawer rail 3 to the caserail 1. Thus, the main ball 20 is by-passed on side thrust loads. Whenthe roller 40 is transmitting side thrust, it has a tractive engagementwith the suspension member 2, thru the axle 41. Thus, any movement ofthe drawer rail with outward side pressure moves the roller in the samedirection at half the speed, and the tractive engagement with thesuspension member 2 thru the axle 41, causes the suspension member totravel with the roller which in effect becomes a propeller roller thesame as main ball 20.

When the suspension assembly is extended, the limit of travel of thesuspension member 2 relative to the case rail 1 is determined by thestop 52 on the case rail and the stop 58 on the suspension member withthe auxiliary 24 between them. Forward travel of the drawer runner withrespect to the suspension member is limited by the stop 53 on thesuspension member and the stop 51 on the drawer rail with the ball 25therebetween. Direct contact between the stops and the auxiliary ballsis prevented by the buffer spring 65 (Fig. 12) a portion of which bufferspring projects both forwardly and rearwardly of each of these auxiliaryballs 24 and 25. That portion of the buffer spring 65 connecting itsforward and rearward portions mounts the bulfer spring 65 on the ball.This is desirable to cushion impact when the drawer is opened or closedsharply and thus has appreciable momentum when it reaches the limit ofits travel.

The forward travel of the auxiliary ball 30 is controlled by theremovable limiter 56 mounted on the case rail 1. As the suspensionassembly is extended,the positioner 59 causes the auxiliary ball 30 totravel the full distance to the limiter 56. Positioners such as thepositioner 59 are necessary in situations where the auxiliary ball isnot at all times under a compression load to cause it to travel with thesuspension. Travel of the auxiliary ball 3% is controlled by the limiter61 when the suspension is moved rearwardly.

Forward travel of auxiliary ball 24 is controlled by the stop 52. Thestop 58 on the suspension member 2 serves as a positioner for auxiliaryball 24. Rearward travel of auxiliary ball 24 is controlled by aremovable limiter 57 on the case channel when the suspension assembly isclosed. Auxiliary ball 24 is positioned by the positioner 69 on thesuspension member when the suspension assembly is closed.

Forward travel of the auxiliary ball 34 is controlled by the limiter 54on the suspension member. The auxiliary ball 34 is positioned by thepositioner 62 on the drawer runner 3 when the suspension assembly is extended. Rearward travel of the ball 34 is controlled by the limiter 55on the suspension member.

Forward travel of the auxiliary ball 25 is limited by the stop 53 whenthe suspension assembly is extended. Auxiliary ball 25 is positioned bythe stop 51. No positioner or limiter is provided for auxiliary ball 25when the suspension assembly is moved to its closed position sinceauxiliary ball 25 is always under load and, therefore, travel with thesuspension assembly is assured.

The limiters 56 and 57 are removably attached to the flange 5 by meansof screws, or other suitable means. Removal of the limiters 56 and 57permits the auxiliary balls 24 and 30 to be removed and the entiresuspension assembly to be taken apart.

At its rearward end, the drawer runner 3 is provided with a stop 66(Fig. 6). The stop 66 contacts the resilient bumper 67 mounted on theupturned flange 68 at the rearward end of the case channel 1 (Figs. 1and 6). The stop 66 and bumper 67 provide a positive stop for backwardtravel of the drawer. The drawer 44 is attached to the suspensionassembly by being seated upon the drawer rail 3 with the prong 69 of thedrawer runner extending up through a matching slot in the drawer.

Operation The purpose of the suspension assembly is to provide apositive horizontal support for the heavy drawer permitting the drawerto be withdrawn its entire length from its cabinet while holding thedrawer level. At the same time it permits the drawer to be opened andclosed with a minimum of effort. To this end, the drawer rail supportsthe drawer throughout substantially the drawers entire length andtransmits the weight of the drawer to the suspension member 2. Thesuspension member 2 provides a beam by which the drawer rail 3 is heldhorizontal and the load of the drawer transmitted to the case rail 1.The case rail 1 supports the suspension member 2 and transmits the loadto the frame of the cabinet.

When the drawer is in its closed position (Fig. 2) the weight of thedrawer is transmitted from the drawer rail 3 to the case rail 1 throughthe main hall 20. Minor loads may be transmitted through the auxiliaryball 31, if the drawer happens to be heavily loaded at the forward endand, thus unbalanced. As the drawer is ex tended, the main ball alongwith the auxiliary balls 24, 25, 30, 31 and 34 move forwardly togetherwith the members of the suspension assembly but with a maximum forwardtravel of only one-half that of the members of the suspension assembly.The ball 20 at all times remains at the pivot point whereby the majorweight of the drawer is transmitted by the ball 20 directly from thedrawer rail 3 to the case rail 1.

In extended position, the auxiliary ball 31 transmits the downwardthrust of the drawer rail 3 to the suspension member 2, acting as theforward support for the drawer load. The main ball 20, thus, always hasa tractive engagement with the suspension member 2, :due to the factthat its upper surface is at all times in contact with the drawer rail 3while the lower surface is at all times in contact with case rail 1.Thus, any movement of the drawer rail 3 moves the main ball 20 in thesame direction at half the speed of the drawer rail. The main ball 20,through its tractive engagement with the upturned lips 22 of thesuspension member 2 causes the suspension member to travel with theball, making it, in effect, a propeller ball, insuring proper travel ofthe suspension member. The auxiliary ball transmits the upward thrust ofthe drawer rail 3 to the suspension member 2. This upward thrust resultsfrom the tendency of the drawer to pivot forwardly about the main ball20. The auxiliary ball 34 keeps the suspension member 2 and drawer rail3 properly spaced and facilitates their relative movement. The auxiliaryball 24 transmits upward thrust from the suspension member 2 to the caserail 1 resulting from the tendency of the suspension assembly to pivotabout the main hall 20 under the downward load of the extended drawer.

When the drawer is unbalanced by heavy loading at its.

rearward end, the drawer may have some tendency to pivot rearwardly. Tolimit this rearward pivoting, the suspension member 2 is provided with aglide 70 (Fig. 4) on its lower rearward end permitting the weight of therearward end of the suepension member to be transmitted to the caserail 1. Upon slight forward movement of the drawer, the center ofbalance will be shifted and the slide 74) caused to rise from the caserail 1.

The auxiliary balls 24 and are each of the same diameter and fill theraceway or track formed between the shoulders 8 and 9 and the upper wallof the suspension member 2 and the wall of the flange 5 of the caserail 1. Thus, the raceway or track within which the auxiliary balls 36and 24 move is substantially square whereby the balls may transmit bothvertical and horizontal thrust loads. The relative size of the balls 24and 30 and the design of the case rail 1 and of the suspension member 2is such that the auxiliary balls 24 and 30 will form a contact betweenthese members before surface contact can occur between them. Theauxiliary balls 25 and 34 are of the same diameter and contact not onlythe shoulders 9 and 13 but also the vertical walls of the suspensionmember 2- and of the drawer rail 3 forming thetrack for these auxiliaryballs. Thus, the auxiliary balls 25 and 34 are also capable oftransmitting both vertical and horizontal loads and of maintainingproper spacing between the drawer rail 3 and suspension member 2. T oaccomplish this, it is obvious that the raceways or tracks for theauxiliary balls 24, 25, 30 and are substantially square. The rollercontacts the vertical wall 23 of the drawer rail 3 and the vertical wallof the case rail 1. Thus, the roller 40 maintains proper horizontalspacing between the drawer rail 3 and the case rail 1 in the lowerportion of the suspension assembly. The auxiliary balls 24, 25, 30 and35 maintain proper horizontal spacing of the members in the upperportion of the suspension assembly. The function of the auxiliary balls30 and 34 is primarily to transmit side thrust and secondarily totransmit vertical loads. The function of the auxiliary balls 24 and 25is primarily to transmit vertical loads and secondarily to transmit sidethrust. The slight downward V-shaping of the track 12 in the case rail 1automatically centers the main ball 20, keeping the entire suspensionproperly aligned vertically and centering the drawer within the openingin the cabinet.

By means of the auxiliary balls 24, 25, 3G and 34 and the roller 40,each of the separate members forming the suspension assembly is properlyspaced and frictional surface to surface contact between these members.is positively eliminated. The entire assembly runs very easily eventhough the whole assembly is subjected to severe side thrust. Not onlydoes this prevent the Wear attendant surface to surface frictionalcontact but it materially reduces sidesway of the drawer. Heretofore,this sidesway or racking has never been successfully prevented in asuspension assembly of practical design nor has the wear and malfunctionattendant metal to metal contact between the various members of thesuspension assemblies been successful eliminated.

The suspension assemblies embodying my invention are utilized in pairs,one assembly on each side of a drawer. The assemblies of each drawercooperate, each one providing the major support against side movementin'its particular direction.

Minor modifications of my invention may be made without departing fromthe principle of my invention. Such modifications are to be consideredas included in the hereinafter appended claims unless these claimsexpressly state otherwise.

I claim:

1. In a telescoping drawer suspension having a case rail, a suspensionmember and a drawer rail, the improvement in said suspension comprising:said case rail, suspension member and drawer rail each being laterallyspaced; said case rail having a vertical portion and a first horizontaloffset; said suspension member having a vertical portion and a secondhorizontal oifset; said first and second olfsets together with saidvertical portions of said case rail and said suspension member providinga first ball raceway of square cross-section; a pair of spaced ballsmounted in said first raceway; said drawer rail having a verticalportion and a third horizontal offset; said second and third offsetstogether with the vertical portions of said suspension member and saiddrawer rail providing a second ball raceway of square cross-section; apair of spaced balls mounted in said second raceway; each of said ballshaving a diameter equal to the width of said raceway; said suspensionmember having a horizontal bottom leg; a vertical axle mounted to saidleg of said suspension member; a roller adapted to rotate about saidaxle; an aperture in the vertical portion of said suspension member andsaid roller extending through said aperture; said roller contacting thevertical portions of both said drawer rail and said case rail.

2. In a telescoping drawer suspension having a case rail, a suspensionmember and a drawer rail, a main ball for supporting said drawer rail onsaid case rail, the improvement in said suspension comprising: said caserail, suspension member and drawer ,ra i-l being laterally spaced; saidcase rail having a vertical portion and a first horizontal offset; saidsuspension member having a vertical portion and a second horizontaloffset; said first and second ofisets together with said verticalportions of said case rail and said suspension member providing a firstball raceway of square cross-section; a pair of spaced balls mounted insaid first raceway; each of said balls having a diameter equal to theWidth of said first raceway; said drawer rail having a vertical portionand a third horizontal ofiset; said second and third offsets togetherwith the vertical portions of said suspension member and said drawerrail providing a second bail raceway of square cross-section; a pair ofspaced balls mounted in said second raceway; each of said balls having adiameter equai to the width of said second raceway; said suspensionmemer having a horizontal bottom leg; a vertical axle secured to saidleg of said suspension member adjacent said main ball; a roller adaptedto rotate about said axle; an aperture in the vertical portion of saidsuspension member and said roller ex ending through said aperture; saidroller contacting the vertical portions of both said drawer rail andsaid case rail.

3. In a telescoping drawer suspension having a case rail, a suspensionmember, and a drawer rail each being laterally spaced one from the otherand each having vertical portions, said case rail and said suspensionmember each having off-set shoulders in their upper portions, saiddrawer rail having an off-set shoulder approximately midway between itsupper and lower ends, the improvement in said combination comprising:said otf-set shoulders and vertical portions forming a pair of trackwayseach of square cross section; balls mounted in each of said track--ways; said balls having a diameter equal to the height and width of saidtrackways, for separating the upper portions of said case rail,suspension member and drawer rail both laterally and vertically; saidsuspension member having a flange at the lower end normal to itsvertical portion; a stationary, vertical pin fixed to said flange ofsaid suspension member; a roller seated on said pin for free horizontalrotation; an aperture in the vertical portion of said suspension memberand said roller projecting through said aperture to contact said caserail; the opposite side of said roller being in contact with said drawerrail, whereby said roller may positively space said rails and suspensionmember from each other.

References Cited in the file of this patent

